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1.
Ecosystem services have gained rapid interest for understanding urban-environment interactions. However, while the term “ecosystem services” is relatively novel, their principles have influenced urban planning for decades. This study assesses the wealth of urban ecosystem services research conducted in the tropical city state of Singapore, in particular their historical local use and implicit and explicit incorporation into land use planning, and shows how Singapore is exporting their experiences to other cities around the world. Singapore is an important model for urban ecosystem services research, as the nation has experienced rapid urban development and has a 100 % urban population. Singapore also historically utilized ecosystem services in urban decision making long before the concept was popularized. For example, forests were conserved since 1868 for climatic regulation and for the watershed protection services provided to Singapore’s first reservoirs, and green spaces have been conserved for cultural ecosystem services since the 1920s. Urban ecosystem services were formally incorporated into national planning in the 1960s through the “Garden City” urban planning vision. Singapore is now a leading case study for tropical urban climatology and carbon sequestration, exporting its experiences globally through bilateral agreements and the construction of eco-cities in China, and the creation and promotion of a global City Biodiversity Index to assess urban ecosystem service provision in cities across the globe. Consolidating and understanding case study cities such as Singapore is important if we are to understand how to incorporate multiple ecosystem services into large scale planning frameworks, and provides an important tropical example in a research field dominated by western, temperate case studies.  相似文献   

2.
Spontaneous vegetation colonizes large areas in and around cities. These unmanaged areas are considered to have low economic value or indicate dereliction, but recent research suggests that these can contribute valuable ecosystem services. This study evaluates indicators of ecosystem services in three habitats: urban spontaneous vegetation (USV), managed lawns, and semi-natural urban forest, in Halifax, Nova Scotia. USV had higher indicator values for habitat provisioning (plant species diversity, invertebrate abundance and taxonomic diversity) than the other habitats. Indicators of climatic regulatory services (albedo and leaf area index) in USV were similar to those in lawn habitats. Organic carbon content of the soils, an indicator of carbon storage, was lowest in USV but only marginally lower than in lawns. Standing biomass, an indicator of production services, was lowest in USV but lawn production may have been overestimated. While USV sites are usually transitory components of the urban landscape, they deserve further consideration due to their provision of ecosystem services, in some cases to a greater extent than conventionally valued urban habitats.  相似文献   

3.
Vegetation has gained importance in respective debates about climate change mitigation and adaptation in cities. Although recently developed remote sensing techniques provide necessary city-wide information, a sufficient and consistent city-wide information of relevant urban ecosystem services, such as carbon emissions offset, does not exist. This study uses city-wide, high-resolution, and remotely sensed data to derive individual tree species information and to estimate the above-ground carbon storage of urban forests in Berlin, Germany. The variance of tree biomass was estimated using allometric equations that contained different levels of detail regarding the tree species found in this study of 700 km2, which had a tree canopy of 213 km2. The average tree density was 65 trees/ha per unit of tree cover and a range from 10 to 40 trees/ha for densely urban land cover. City-wide estimates of the above-ground carbon storage ranged between 6.34 and 7.69 tC/ha per unit of land cover, depending on the level of tree species information used. Equations that did not use individually localized tree species information undervalued the total amount of urban forest carbon storage by up to 15 %. Equations using a generalized estimate of dominant tree species information provided rather precise city-wide carbon estimates. Concerning differences within a densely built area per unit of land cover approaches using individually localized tree species information prevented underestimation of mid-range carbon density areas (10–20 tC/ha), which were actually up to 8.4 % higher, and prevented overestimation of very low carbon density areas (0–5 tC/ha), which were actually up to 11.4 % lower. Park-like areas showed 10 to 30 tC/ha, whereas land cover of very high carbon density (40–80 tC/ha) mostly consisted of mixed peri-urban forest stands. Thus, this approach, which uses widely accessible and remotely sensed data, can help to improve the consistency of forest carbon estimates in cities.  相似文献   

4.
Accurate estimates of biomass in urban forests can help improve strategies for enhancing ecosystem services. Landscape heterogeneity, such as land-cover types and their spatial arrangements, greatly affects biomass growth, and it complicates the estimation of biomass. Application of LiDAR data is a typical approach for mapping forest biomass and carbon stocks across heterogeneous landscapes. However, little is known about how urban land uses and pattern impact biomass and estimates derived from LiDAR analysis. In this study, we examined the relationship between LiDAR-derived biomass and dominant land-cover types using field-measured estimates of aboveground forest biomass in an urbanized region of North Carolina, USA. Three objectives drove this research: 1) we examined the local effects of dominant land cover types on urban forest biomass; 2) we identified the spatial scale at which dominant land cover influences biomass estimates; 3) we investigated whether the fine-scale, spatial heterogeneity of the urban landscape contributed to forest biomass. We used multiple linear regression to relate field-measured biomass to LiDAR metrics and land cover densities derived from Landsat and LiDAR data. The biomass model developed from variables derived from LiDAR first returns produced biomass estimates similar to using all LiDAR returns. Although three land-cover types (impervious surface, managed clearings, and farmland) exhibited a negative relationship with biomass, only impervious surface was statistically significant. The biomass model that used impervious surface densities between 100 m and 175 m radial buffers produced the highest adjusted R 2 with lower RMSE values. Our study suggests that impervious surface impacted forest biomass estimates considerably in urbanizing landscapes with the greatest effect between 100 and 175 m from a forest stand. Managed clearing and farmland types negatively impacted biomass estimation albeit not as strongly as impervious surface. Overall, we found that accounting for impervious surface density and its proximity to forest in biomass models may improve urban forest biomass estimates.  相似文献   

5.

Urban forests are valuable spaces for species conservation, protection of local biodiversity and provision of ecosystem services. However, they are also vulnerable to the impact of extreme climate events like hurricanes. Understanding how urban forests are responding to hurricane disturbances is crucial to improve their design, management, and resilience. Here we analyzed pre-and post-hurricane vegetation surveys in 52 residential yards in San Juan to assess urban forest responses after Hurricanes Irma and María impacted Puerto Rico in 2017. We used these surveys to compare vegetation structure and composition (including species-specific mortality and damage rates) and to quantify changes in the ecosystem services provided by these yards. We found that hurricane disturbances significantly altered the structure but not the composition of yard vegetation. We detected a 27% reduction and 31% mortality of standing stems, and a significant reduction in plants health. Yard species composition was dominated by non-native species and this trend did not change with hurricane disturbance. Changes in vegetation structure translated into substantial reductions in ecosystem services. Food provision, an important service provided by a large proportion of yards before the hurricane, reported the highest reduction (41.9%) while carbon storage was the service that changed the least (9%). Our combined results emphasize the key role played by residential yards providing ecosystem services in tropical cities and call for further efforts to manage private and public urban forests in ways that may ensure their resilience to mitigate extreme climate events, provide multiple ecosystem services, and promote long-term urban sustainability.

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6.
Deforestation is responsible for a substantial fraction of global carbon emissions and changes in surface energy budgets that affect climate. Deforestation losses include wildlife and human habitat, and myriad forest products on which rural and urban societies depend for food, fiber, fuel, fresh water, medicine, and recreation. Ecosystem services gained in the transition from forests to pasture and croplands, however, are often ignored in assessments of the impact of land cover change. The role of converted lands in tropical areas in terms of carbon uptake and storage is largely unknown. Pastures represent the fastest-growing form of converted land use in the tropics, even in some areas of rapid urban expansion. Tree biomass stored in these areas spans a broad range, depending on tree cover. Trees in pasture increase carbon storage, provide shade for cattle, and increase productivity of forage material. As a result, increasing fractional tree cover can provide benefits land managers as well as important ecosystem services such as reducing conversion pressure on forests adjacent to pastures. This study presents an estimation of fractional tree cover in pasture in a dynamic region on the verge of large-scale land use change. An appropriate sampling interval is established for similar studies, one that balances the need for independent samples of sufficient number to characterize a pasture in terms of fractional tree cover. This information represents a useful policy tool for government organizations and NGOs interested in encouraging ecosystem services on converted lands. Using high spatial resolution remotely sensed imagery, fractional tree cover in pasture is quantified for the municipality of Rio Branco, Brazil. A semivariogram and devolving spatial resolution are employed to determine the coarsest sampling interval that may be used, minimizing effects of spatial autocorrelation. The coarsest sampling interval that minimizes spatial dependence was about 22 m. The area-weighted fractional tree cover for the study area was 1.85 %, corrected for a slight bias associated with the coarser sampling resolution. The pastures sampled for fractional tree cover were divided between ‘high’ and ‘low’ tree cover, which may be the result of intentional incorporation of arboreal species in pasture. Further research involving those ranchers that have a higher fractional tree cover may indicate ways to promote the practice on a broader scale in the region.  相似文献   

7.
Urban forest structure,ecosystem services and change in Syracuse,NY   总被引:1,自引:0,他引:1  
The tree population within the City of Syracuse was assessed using a random sampling of plots in 1999, 2001 and 2009 to determine how the population and the ecosystem services these trees provide have changed over time. Ecosystem services and values for carbon sequestration, air pollution removal and changes in building energy use were derived using the i-Tree Eco model. In addition, photo interpretation of aerial images was used to determine changes in tree cover between the mid-1990s and 2009. Between the mid-1990s and 2003, tree cover in Syracuse exhibited a decline from 27.5 to 25.9 %, but subsequently increased to 26.9 % by 2009. The total tree population exhibited a similar pattern, dropping from 881,000 trees in 1999 to 862,000 in 2001, and then increasing to 1,087,000 trees in 2009. Most of this increase in the urban tree population is due to invasive or pioneer trees species, particularly Rhamnus cathartica, which has more than tripled in population between 2001 and 2009. Insects such as gypsy moth and emerald ash borer pose a substantial risk to altering future urban forest composition. The annual ecosystem services provided by the urban forest in relation to carbon sequestration, air pollution removal and reduction in building energy use are estimated at about $2.4 million per year. An improved understanding of urban forests and how they are changing can facilitate better management plans to sustain ecosystem services and desired forest structure for future generations.  相似文献   

8.
Functional diversity and composition of soil bacterial communities affect important soil biogeochemical processes. In natural and semi-natural ecosystems, variations in habitat complexity have been shown to significantly impact both litter and soil bacterial communities. However, this remains largely untested in urban ecosystems, where human management can lead to habitat complexity combinations unobserved in rural ecosystems. We established 10 research plots in low-complexity park, high-complexity park, and high-complexity remnant habitat types (n = 30) in Melbourne, Australia. The use of organic carbon substrates by soil and litter bacteria was measured using EcoPlates to investigate the effects of habitat complexity upon metabolic functional diversity and functional composition of bacterial communities of i) soil and ii) one-year old litter. Direct and indirect effects of habitat complexity, microclimate and decomposition status upon litter microbial functional diversity and composition were also modelled using path analysis. Soil bacterial communities had significantly higher functional diversity compared to litter bacterial communities, but no significant effect of habitat complexity was apparent. The functional composition of soil bacterial communities was not affected by habitat complexity. In contrast, the functional composition of litter bacterial communities in high complexity parks and remnants was significantly different from that in low-complexity parks. The functional composition of litter bacterial communities, but not their diversity, was directly affected by habitat complexity and microclimate as well as their indirect effects upon the decomposition status of litter. Human management of urban habitat complexity can alter the functional composition of litter and soil bacterial communities without affecting their functional diversity. While this can have significant impacts on bacteria-regulated processes and ecosystem services, it also suggests that urban bacterial communities might be able to adjust to further environmental and climatic changes affecting urban ecosystems.  相似文献   

9.
Coastal areas are rapidly developing due to population growth and the appeal of coastlines. In order to gain insight into how land use/cover affects carbon (C) storage in a coastal context, we examined soil and vegetation C and soil nitrogen (N) across land uses near Apalachicola, FL. Forested wetlands had the greatest soil C and N storage, while natural pine forests and pine plantations had the least. In paired plots, urban lawns had significantly greater mineral soil N content compared to urban forest remnants. Total ecosystem C (soil + vegetation) was higher in forested wetlands than all other land uses/covers combined due to the high organic content of those wetland soils. Urban forest remnants and lawns had greater total ecosystem C than natural pine forests and pine plantations, which likely reflects the differential influence of prescribed fire and less frequent anthropogenic disturbances between the rural and urban areas, respectively. Projections of land use change in Franklin County, FL combined with these data suggest that increases in C storage are possible with continued urbanization along the Gulf Coast, if forest remnants are left and lawns are incorporated in built-up areas. However, this study does not account for C emissions during land conversion, or any emissions associated with maintaining urban built-up and residential areas. A better understanding of land use/cover influences on C pools has applications for planning and development, as well as ecological and environmental protection in the region.  相似文献   

10.
Urbanization impacts on the structure and function of forested wetlands   总被引:3,自引:0,他引:3  
The exponential increase in population has fueled a significant demographic shift: 60% of the Earth's population will live in urban areas by 2030. While this population growth is significant in its magnitude, the ecological footprint of natural resource consumption and use required to sustain urban populations is even greater. The land use and cover changes accompanying urbanization (increasing human habitation coupled with resource consumption and extensive landscape modification) impacts natural ecosystems at multiple spatial scales. Because they generally occupy lower landscape positions and are linked to other ecosystems through hydrologic connections, the cascading effects of habitat alteration on watershed hydrology and nutrient cycling are particularly detrimental to wetland ecosystems. I reviewed literature relevant to these effects of urbanization on the structure and function of forested wetlands. Hydrologic changes caused by habitat fragmentation generally reduce species richness and abundance of plants, macroinvertebrates, amphibians, and birds with greater numbers of invasives and exotics. Reduction in soil saturation and lowered water tables result in greater nitrogen mineralization and nitrification in urban wetlands with higher probability of NO 3 export from the watershed. Depressional forested wetlands in urban areas can function as important sinks for sediments, nutrients, and metals. As urban ecosystems become the predominant human condition, there is a critical need for data specific to urban forested wetlands in order to better understand the role of these ecosystems on the landscape.  相似文献   

11.
Urban Ecosystems - This study was conducted to explore the ecosystem services of urban forests in Adama city, central Ethiopia. Attempts were made to quantify the carbon storage and sequestration,...  相似文献   

12.
Urban forests adjacent to interstate corridors are understudied ecosystems across cities. Despite their small area, these forests may be strategically located to provide large ecosystem services due to their ability to act as a barrier against air pollutants and noise as well as to provide flood control. The woody vegetation composition and structure of forests adjacent to urban interstates is an important determinant of their ability to provide these services. However, these forest communities may be particularly susceptible to the introduction of exotic invasive species via the interstate and the surrounding city that can potentially alter current and future forest composition. The purpose of this study was to investigate the distribution of native and exotic woody vegetation and tree regeneration in forests along three interstate corridors in Louisville, KY, and to determine potential factors (e.g., traffic density) that are correlated with patterns in the woody vegetation community. We found the most important determinants of vegetation composition along these interstate corridors were the distance from the city center and the presence of an exotic invasive shrub, Amur honeysuckle (Lonicera maackii). Compared with forested plots within 10 km of the city center, plots further from the city center had 81% lower stem density of Amur honeysuckle, 96% higher tree seedling regeneration, and 51% greater woody plant species richness. The primarily native species composition of adult trees in forests alongside urban interstates in Louisville and the regeneration of native tree species provide optimism that these forests can maintain native species while experiencing multiple impacts from the interstate as well as from the surrounding city, emphasizing their important potential for maintaining natural forest functions across the urban landscape.  相似文献   

13.
On-going human population growth and changing patterns of resource consumption are increasing global demand for ecosystem services, many of which are provided by soils. Some of these ecosystem services are linearly related to the surface area of pervious soil, whereas others show non-linear relationships, making ecosystem service optimization a complex task. As limited land availability creates conflicting demands among various types of land use, a central challenge is how to weigh these conflicting interests and how to achieve the best solutions possible from a perspective of sustainable societal development. These conflicting interests become most apparent in soils that are the most heavily used by humans for specific purposes: urban soils used for green spaces, housing, and other infrastructure and agricultural soils for producing food, fibres and biofuels. We argue that, despite their seemingly divergent uses of land, agricultural and urban soils share common features with regards to interactions between ecosystem services, and that the trade-offs associated with decision-making, while scale- and context-dependent, can be surprisingly similar between the two systems. We propose that the trade-offs within land use types and their soil-related ecosystems services are often disproportional, and quantifying these will enable ecologists and soil scientists to help policy makers optimizing management decisions when confronted with demands for multiple services under limited land availability.  相似文献   

14.
Addis Ababa is a highland city with varied topography and landscape features. The mountains that surround the city are covered with urban forest of different types. These forests are providing various ecosystem services for the urban and peri-urban population of the city. Apart from surface temperature regulating function of the green spaces of Addis Ababa, no quantitative assessment of the carbon sequestration and soil protection ecosystem services provided by the urban forest has been conducted to date. The aim of this study was to assess selected ecosystem services such as carbon storage potential, habitat support and soil erosion protection provided by different categories of urban forest of Addis Ababa. The result showed that carbon density in the study area varied with forest categories viz. 293tons/ha, 142tons/ha and 132tons/ha in the dense, medium and open forest types respectively. The Shannon-Wiener diversity index is3.24 for Junipers dominated forest, 2.98 for mixed forest and 2.76 for Eucalyptus dominated forest. The formation of soil erosion features is significantly different among the Eucalyptus forest, Juniperus forest and Mixed forest where high incidence of soil erosion was recorded in the Eucalyptus forest. Therefore, irrespective of the environmental factors such as slope, aspect and elevation differences, there is an association between Eucalyptus forest cover and high soil erosion features. To ensure sustainable supply of ecosystem services and maintain a balanced urban environment, all green spaces in the city should be ecologically networked and diversified. Therefore, assessment of ecosystem services provided essential information for effective planning of the green space in terms of species composition and interconnectivity.  相似文献   

15.
Rapid urbanisation and climate change have motivated the development of urban green infrastructure (UGI) as a planning strategy to support the wellbeing of urban people and ecosystems while parallel adapting cities to climate change. Forest (tree-covered areas >0.5 ha) is a key UGI component that afford a wider range of ecosystem services and mitigate urban heat islands more effectively than non-wooded green spaces. However, understanding of spatial configurations (variation in patch size and frequency) of forests across the gradient of urbanisation and between cities is limited to case studies. This represents a considerable knowledge gap for identification of general patterns that can inform integration of forest resources in UGI planning that have value beyond the individual city level. In this study we used Geographic Information Systems to explore the spatial configuration of forests across cities located within landscapes characterised by different levels of anthropogenic modification (degree of forest cover) and socio-political contexts, i.e. all Danish and Swedish cities >10,000 inhabitants (n = 176). We applied general linear modelling to investigate the relationship between forest cover, patch size and frequency with 1) regional landscape type, 2) demographic trends 1960–2010, and 3) the gradient of urbanisation (measured in three zones: urban core (0.2 km from city boundary), urban fringe (0.2–2 km), and urban periphery (2–5 km)). Regardless of demographic trends, forest cover was lowest in cities settled in large-scale agricultural regions, higher in regions with mosaics of forest and farming, and highest in forest-dominated regions. However, in all cities forest cover was lowest in the urban zone and peaked on the urban fringe rather than on the urban periphery. Furthermore, pocket woods (0.5–2 ha) accounted for over 50 % of patches in all three urban zones, irrespective of regional landscape type. We conclude by discussing how these general patterns could inform strategies for integration of urban forests in UGI planning.  相似文献   

16.
Although ecosystem services have been intensively examined in certain domains (e.g., forests and wetlands), little research has assessed ecosystem services for the most dominant landscape type in urban ecosystems—namely, residential yards. In this paper, we report findings of a cross-site survey of homeowners in six U.S. cities to 1) examine how residents subjectively value various ecosystem services, 2) explore distinctive dimensions of those values, and 3) test the urban homogenization hypothesis. This hypothesis posits that urbanization leads to similarities in the social-ecological dynamics across cities in diverse biomes. By extension, the thesis suggests that residents’ ecosystem service priorities for residential landscapes will be similar regardless of whether residents live in the humid East or the arid West, or the warm South or the cold North. Results underscored that cultural services were of utmost importance, particularly anthropocentric values including aesthetics, low-maintenance, and personal enjoyment. Using factor analyses, distinctive dimensions of residents’ values were found to partially align with the Millennium Ecosystem Assessment’s categories (provisioning, regulating, supporting, and cultural). Finally, residents’ ecosystem service priorities exhibited significant homogenization across regions. In particular, the traditional lawn aesthetic (neat, green, weed-free yards) was similarly important across residents of diverse U.S. cities. Only a few exceptions were found across different environmental and social contexts; for example, cooling effects were more important in the warm South, where residents also valued aesthetics more than those in the North, where low-maintenance yards were a greater priority.  相似文献   

17.
Many studies have analyzed the benefits, costs, and carbon storage capacity associated with urban trees. These studies have been limited by a lack of research on urban tree biomass, such that estimates of carbon storage in urban systems have relied upon allometric relationships developed in traditional forests. As urbanization increases globally, it is becoming important to more accurately evaluate carbon dynamics in these systems. Our goal was to understand the variability and range of potential error associated with using allometric relationships developed outside of urban environments. We compared biomass predictions from allometric relationships developed for urban trees in Fort Collins, Colorado to predictions from allometric equations from traditional forests, at both the individual species level and entire communities. A few of the equations from the literature predicted similar biomass to the urban-based predictions, but the range in variability for individual trees was over 300%. This variability declined at increasingly coarse scales, reaching as low as 60% for a street tree community containing 11 tree species and 10, 551 trees. When comparing biomass estimates between cities that implement various allometric relationships, we found that differences could be a function of variability rather than urban forest structure and function. Standardizing the methodology and implementing averaged equations across cities could be one potential solution to reducing variability; however, more accurate quantification of biomass and carbon storage in urban forests may depend on development of allometric relationships specifically for urban trees.  相似文献   

18.
Sacred sites are important not only for their traditional, spiritual or religious significance, but may also potentially be valuable for biodiversity conservation in human transformed landscapes. Yet, there has been little consideration of sacred sites in urban areas in this respect. Consequently, to better understand the ecosystem service and conservation value of urban sacred sites, inventories of their floral communities are needed. We examined the richness, composition and structure of the trees and shrubs in 35 urban churchyards and cemeteries in the City of Saints (Grahamstown). The combined area of urban sacred sites (38.7 ha) represented 2.2% of the city area and 13.6% of the public green space area. Species richness of woody plants was high, albeit dominated by non-native species. Levels of similarity among sites were low, indicating the effects of individual management regimens. There was no relationship between age of the site and measured attributes of the vegetation, nor were there any significant differences in vegetation among different religious denominations. However, the basal area and number of woody plants was significantly related to site size. These results indicate the significant heterogeneity of urban sacred sites as green spaces within the urban matrix. The significance of this heterogeneity in providing ecosystem services to users of sacred sites and the broader urban communities requires further investigation.  相似文献   

19.
Riparian forests are vital for maintaining healthy stream ecosystems; acting as buffers against nutrient and contaminant inputs, contributing energy subsidies and providing favorable instream habitat conditions. In urban catchments riparian forests are often degraded or cleared, removing the ecosystem functions the forest provides. Intact riparian forest along urban waterways, may mitigate some aspects of degradation associated with an urbanized catchment. In Bulimba Creek, an urbanized catchment in southeast Queensland, Australia, we investigated some ecosystem functions provided by riparian forest. We found that during baseflow periods a forested riparian corridor provided energy subsidies to the stream through litterfall and had a controlling influence on instream production through shading. Denitrification potential of benthic sediments increased with increasing levels of woody debris and organic matter, deposited from riparian vegetation. Denitrification was nitrate limited, indicating some potential to reduce nitrate loads in the stream. Riparian soils also showed moderate denitrification potential; which, through management strategies, could be utilized to reduce excess nitrate loads. These results suggest that riparian forests provide important functions for urban streams; highlighting the importance of conserving forest remnants in urban landscapes and the usefulness of replanting degraded riparian forest to enhance stream health and habitat condition.  相似文献   

20.
Urban Ecosystems - Urban ecosystems and ecosystem services have received little research attention in South Asian countries where rapid urban development is currently problematic. We developed a...  相似文献   

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